Displaying Time Zones in WPF/C#. Discover Daylight Savings Time Offset

c# wpf datetime timezone
Created : 7/11/2022
Source : Stack Overflow

Question

I am having trouble understanding how the System Registry can help me convert a DateTime object into the a corresponding TimeZone. I have an example that I've been trying to reverse engineer but I just can't follow the one critical step in which the UTCtime is offset depending on Daylight Savings Time.

I am using .NET 3.5 (thank god) but It's still baffling me.

Thanks

EDIT: Additional Information: This question was for use in a WPF application environment. The code snippet I left below took the answer example a step further to get exactly what I was looking for.

Questioned by : discorax

Answer

Here is a code snippet in C# that I'm using in my WPF application. This will give you the current time (adjusted for Daylight Savings Time) for the time zone id you provide.

// _timeZoneId is the String value found in the System Registry.
// You can look up the list of TimeZones on your system using this:
// ReadOnlyCollection<TimeZoneInfo> current = TimeZoneInfo.GetSystemTimeZones();
// As long as your _timeZoneId string is in the registry 
// the _now DateTime object will contain
// the current time (adjusted for Daylight Savings Time) for that Time Zone.
string _timeZoneId = "Pacific Standard Time";
DateTime startTime = DateTime.UtcNow;
TimeZoneInfo tst = TimeZoneInfo.FindSystemTimeZoneById(_timeZoneId);
_now = TimeZoneInfo.ConvertTime(startTime, TimeZoneInfo.Utc, tst);

This is the code snippit I ended up with. Thanks for the help.

Answered by : discorax
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